1. Field of the Invention
The present invention relates to an object (a product including a machine, a manufacture, and a composition of matter) and a method (a process including a simple method and a production method). In particular, one embodiment of the present invention relates to a power storage device, a semiconductor device, a light-emitting device, a display device, an electrical device, a driving method thereof, or a manufacturing method thereof.
In this specification, a power storage device refers to any device which can store power, and a secondary battery (also referred to as a storage battery), a structure provided with a control circuit relating to charging and discharging, and a structure provided with a power supply circuit such as a converter are all included in power storage devices.
In this specification, a semiconductor device refers to any device which can function by utilizing semiconductor characteristics; an electrooptic device, a light-emitting display device, a semiconductor circuit, and an electronic device are all included in semiconductor devices.
2. Description of the Related Art
In recent years, a variety of power storage devices, for example, secondary batteries such as lithium-ion secondary batteries, lithium-ion capacitors, and air cells have been actively developed. In particular, demand for lithium-ion secondary batteries with high output and high energy density has rapidly grown with the development of the semiconductor industry, for electronic devices, for example, portable information terminals such as cell phones, smartphones, and laptop computers, portable music players, and digital cameras; medical equipment; next-generation clean energy vehicles such as hybrid electric vehicles (HEVs), electric vehicles (EVs), and plug-in hybrid electric vehicles (PHEVs); and the like. The lithium-ion secondary batteries are essential as rechargeable energy supply sources for today's information society.
A lithium-ion secondary battery includes a negative electrode, a positive electrode, and an electrolyte solution including a non-aqueous electrolyte containing a lithium salt and an organic solvent, for example. A method for manufacturing a lithium-ion battery is disclosed in Patent Document 1, for example.